Designing Disaster Recovery Clusters using Metroclusters and Continentalclusters, Reprinted October 2011 (5900-1881)

This will halt any applications, remove any floating IP addresses, unmount file systems and
deactivate volume groups as programmed into the package control files. The status of the
paired volumes will remain SMPL at the recovery site and PSUE at the primary site.
2. Start the cluster at the primary site. Assuming they have been properly configured the
Continentalclusters primary packages should not start. The monitor package should start
automatically.
3. Since the paired volumes have a status of SMPL at both the primary and recovery sites, the
P9000 or XP views the two halves as unmirrored. From a system at the primary site, manually
create the paired volume.
# paircreate -g <dev-grp-name> -f <fence-level> -vr -c 15
See the XP Raid Manager user’s guide on more paircreate command options.
Since the most current data will be at the remote or recovery site, this will synchronize the
data from the remote or recovery site (use of the -vr option directs the command to synchronize
from the remote site). Wait for the synchronization process to complete before proceeding to
the next step. Failure to wait for the synchronization to complete will result in the package
failing to start in the next step.
4. Manually start the Continentalclusters primary packages at the primary site.
# cmrunpkg <pkg_name>
The control script is programmed to handle this case. The control script recognizes that the
paired volume is synchronized and will proceed with the programmed package startup.
5. Ensure that monitor packages are running at both sites.
Maintaining the Continuous Access P9000 and XP Data Replication Environment
Resynchronizing
After certain failures, data are no longer remotely protected. In order to restore disaster-tolerant
data protection after repairing or recovering from the failure, you must manually run the command
pairresync. This command must successfully complete for disaster-tolerant data protection to be
restored. Following is a partial list of failures that require running pairresync to restore
disaster-tolerant data protection:
• failure of ALL Continuous Access links without restart of the application
• failure of ALL Continuous Access links with Fence Level DATA with restart of the application
on a primary host
• failure of the entire recovery Data Center for a given application package
• failure of the recovery P9000 or XP disk array for a given application package while the
application is running on a primary host
Following is a partial list of failures that require full resynchronization to restore disaster-tolerant
data protection. Full resynchronization is automatically initiated by moving the application package
back to its primary host after repairing the failure.
• failure of the entire primary Data Center for a given application package
• failure of all of the primary hosts for a given application package
• failure of the primary P9000 and XP disk array for a given application package
• failure of all Continuous Access links with application restart on a secondary host
208 Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access for P9000 and XP